package cn.pegasus.teamwork.weixinpay.util;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Random;
import java.util.Set;
import java.util.SortedMap;

import org.apache.http.NameValuePair;

import cn.pegasus.teamwork.weixinpay.configure.WxPayConfig;
@SuppressWarnings("unused")
public class MD5Util {

	@SuppressWarnings("rawtypes")
	public static String createSign(SortedMap<Object, Object> parameters, String key) {
		StringBuffer sb = new StringBuffer();
		Set es = parameters.entrySet();// 所有参与传参的参数按照accsii排序（升序）
		Iterator it = es.iterator();
		while (it.hasNext()) {
			Map.Entry entry = (Map.Entry) it.next();
			String k = (String) entry.getKey();
			Object v = entry.getValue();
			if (null != v && !"".equals(v) && !"sign".equals(k) && !"key".equals(k)) {
				sb.append(k + "=" + v + "&");
			}
		}
		sb.append("key=" + key);
		String sign = MD5Util.MD5Encode(sb.toString(), WxPayConfig.CHARTSET).toUpperCase();
		return sign;
	}

	private static String byteArrayToHexString(byte b[]) {
		StringBuffer resultSb = new StringBuffer();
		for (int i = 0; i < b.length; i++)
			resultSb.append(byteToHexString(b[i]));

		return resultSb.toString();
	}

	private static String byteToHexString(byte b) {
		int n = b;
		if (n < 0)
			n += 256;
		int d1 = n / 16;
		int d2 = n % 16;
		return hexDigits[d1] + hexDigits[d2];
	}

	public static String MD5Encode(String origin, String charsetname) {
		String resultString = null;
		try {
			resultString = new String(origin);
			MessageDigest md = MessageDigest.getInstance("MD5");
			if (charsetname == null || "".equals(charsetname))
				resultString = byteArrayToHexString(md.digest(resultString.getBytes()));
			else
				resultString = byteArrayToHexString(md.digest(resultString.getBytes(charsetname)));
		} catch (Exception exception) {
		}
		return resultString;
	}

	private static final String hexDigits[] = { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "a", "b", "c", "d",
			"e", "f" };
	
	
	 public static String GetMD5Code(String strObj) {
	        String resultString = null;
	        try {
	            resultString = new String(strObj);
	            MessageDigest md = MessageDigest.getInstance("MD5");
	            // md.digest() 该函数返回值为存放哈希值结果的byte数组
	            resultString = byteArrayToHexString(md.digest(strObj.getBytes()));
	        } catch (NoSuchAlgorithmException ex) {
	            ex.printStackTrace();
	        }
	        return resultString;
	    }
	 
	 public final static String getMessageDigest(byte[] buffer) {
			char hexDigits[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
			try {
				MessageDigest mdTemp = MessageDigest.getInstance("MD5");
				mdTemp.update(buffer);
				byte[] md = mdTemp.digest();
				int j = md.length;
				char str[] = new char[j * 2];
				int k = 0;
				for (int i = 0; i < j; i++) {
					byte byte0 = md[i];
					str[k++] = hexDigits[byte0 >>> 4 & 0xf];
					str[k++] = hexDigits[byte0 & 0xf];
				}
				return new String(str);
			} catch (Exception e) {
				return null;
			}
		}
	 
	 
	//时间戳
	 public static long genTimeStamp() {
		return System.currentTimeMillis() / 1000;
	}
	 //随机数
	 public static String genNonceStr() {
		Random random = new Random();
		return MD5Util.getMessageDigest(String.valueOf(random.nextInt(10000)).getBytes());
	}
	
	 public static String genAppSign(List<NameValuePair> params) {
		StringBuilder sb = new StringBuilder();
		for (int i = 0; i < params.size(); i++) {
			sb.append(params.get(i).getName());
			sb.append('=');
			sb.append(params.get(i).getValue());
			sb.append('&');
		}
		sb.append("key=");
		sb.append(WxPayConfig.KEY);

		String appSign = MD5Util.getMessageDigest(sb.toString().getBytes()).toUpperCase();
		return appSign;
	}

}
